Weaning from Mechanical Ventilation

Abstract

For many critically ill patients admitted to an intensive care unit, the insertion of an endotracheal tube and the initiation of mechanical ventilation (MV) can be lifesaving procedures. Subsequent patient care often requires intensivists to manage the complex interaction of multiple failing organ systems. The shift in the intensivists' focus toward the discontinuation of MV can thus occur late in the course of critical illness. The dangers of MV, however, make it imperative to wean patients at the earliest possible time. Premature weaning trials, however, trigger significant respiratory distress, which can cause setbacks in the patient's clinical course. Premature extubation is also risky. To reduce delayed weaning and premature extubation, a three-step diagnostic strategy is suggested: measurement of weaning predictors, a trial of unassisted breathing (T-tube trial), and a trial of extubation. Since each step constitutes a diagnostic test, clinicians must not only command a thorough understanding of each test but must also be aware of the principles of clinical decision making when interpreting the information generated by each step. Many difficult aspects of pulmonary pathophysiology encroach on weaning management. Accordingly, weaning commands sophisticated, individualized care. Few other responsibilities of an intensivist require a more analytical effort and carry more promise for improving patient outcome than the application of physiologic principles in the weaning of patients.

APACHE II score cannot predict successful weaning from prolonged mechanical ventilation

“…On the one hand, the dangers of mechanical ventilation make it an imperative to wean patients at the earliest possible time. 17 On the other hand, premature weaning and extubation can trigger significant respiratory distress, which can cause setbacks in the patient’s clinical course, including reinstitution of ventilator support and hemodynamic instability. 17 These factors correspond with higher mortality and prolonged ICU length of stay.…”

“… 17 On the other hand, premature weaning and extubation can trigger significant respiratory distress, which can cause setbacks in the patient’s clinical course, including reinstitution of ventilator support and hemodynamic instability. 17 These factors correspond with higher mortality and prolonged ICU length of stay. 18 Therefore, following the current guidelines, 14 we avoided an aggressive approach for early extubation, as reflected by a slightly longer weaning period, when compared to the existing literature data.…”

Influence of ventilatory strategies on outcomes and length of hospital stay: assist-control and synchronized intermittent mandatory ventilation modes

“…A study from 2018 showed that SIMV is rarely used during ventilator weaning worldwide [9]. The comparison between SIMV and PSV during traditional ventilator weaning demonstrated inferior performance of the SIMV mode, which presents greater respiratory muscle work [25], as it provides inadequate rest to the respiratory muscles [7], higher incidence of asynchronies and prolonged hospitalization and MV [7,25].…”

“…However, especially in prolonged MV [3], it is associated with severe complications [2,4]. Ventilator weaning should rest on a balance between daring and safety [5,6], avoiding premature extubation or late weaning [7]. Importantly, information on MV in emerging countries is rather limited [8], and Brazil has a high mortality rate associated with the use of MV, showing an association with advanced age, high disease severity scores, tracheostomy, prolonged MV and medical diagnoses [8].…”

Surface electromyographic evaluation of the neuromuscular activation of the inspiratory muscles during progressively increased inspiratory flow under inspiratory-resistive loading

“…Abnormally rapid respiration (tachypnea) may arise due to several pathophysiological conditions, such as fever, arterial hypoxemia, metabolic acidosis, anxiety, atelectasis, and pain (42). An extremely large increase in the inspiratory rate may lead to more serious problems (30,37). In such situations, the tidal volume moderately decreases and the breathing frequency substantially increases with increases in minute ventilation (20,38).…”